Offset grip for split dies and method of making same



95 w. A. BARNES 2,772,095

FF OR SPLIT DIES AND METHOD OF MAKING S-AME Filed June so, 2 Sheets-Sheet INVENT A. BAR

United States Parent' O FFSET GRIP FOR SPLIT DIES AND METHOD OF MAKING SAME William A. Barnes, Utica, N. Y., assignor to Utica Drop Forge & Tool Corporation, a corporation of New York Application June 30, 1953, Serial No. 365,150

4 Claims. (Cl. 279-57) This invention relates in general to holding and forming dies of multiple parts adapted to close upon a workpiece holding area, and relates more specifically to split taper dies for grippng a longitudinal workpiece and upsetting the end of the workpiece, such as in the butt welding of two such workpieces by upsetting the two against one another.

An object of this invention is to provide split workpiece holding dies for better gripping of a longitudinal workpiece held thereby without deleterious deforming of the workpiece.

Another object of this invention is to provide a wavering workpiece path through split holding dies to thereby increase the resistance to longitudinal slipping movement of the workpiece being held.

Still another object ofthis invention is to provide a convenient and inexpensive means for producing an irregular wall surface in a workpiecevholding cavty of split holding dies.

Other objects and a fuller Understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a front end View of a tapered split die of two parts which embodies features, and is made by the process of this invention; v

Figure 2 is one die member as viewed from line 2-2 of Figure 1;

Figure 3 is one die member as viewed from line 3-3 of Figure 1;

Figure 4 is a back end View of a tapered split die of two parts which embodies features, and is made by the process of this invention;

Figure 5 is a side view of a rotatable mandrel having spaced abrasive portions;

Figure 6 is a sectonal View through a split two-piece cone die assembled in a staggered relative longitudinal position upon the mandrel of Figure 5;

Figure 7 is a sectonal view through a split two-piece cone die assembled in a staggered relative longitudinal position upon an alternate type of cutting mandrel;

Figure 8 is a sectonal view of the dies made with the mandrel of Figure 5 according to this invention in use for butt welding of wires at a temperature less than normal welding temperature; and

Figura 9 is a sectonal view of the dies made With the mandrel of Figure 6 in use for butt welding of wires at a temperature less than normal welding temperature.

Splt dies of various types have long been employed for holding workpieces. However, there has recently been developed a process for welding workpieces, such as wires, at a temperature below the normal welding temperature of the workpieces, by forcing properly cleaned and conditioned workpieces together under conditions of confined flow and high pressure to form a solid phase bond of unusual characteristc. In the process of joining the workpieces, there is required a considerable pressure and, consequently, the holding dies must grip 2,77Z,095 Patented Nov. 27, 1956 the workpieces with an exceptionally strong grip 'and yet not deleteriously deform the workpieces. The workpiece holding cavty of such split dies have been roughened by an electric needle, and other similar processes, in order to attempt to produce a strong anti-slip grip upon'the workpieces.

According to this invention, the dies are formed with lateral recesses which cause the workpiece to assume a wavering path through the dies in order to increase the resistance to longitudinal slippage to a considerable degree.

In order to illustrate the concept of the invention, the production of the improved work holding cavty of this invention is illustrated in conjunction With a tapered split die 10. The split die 10 comprises a half diell and a half die 12 with cooperating surfaces mated together as illustrated in Figures 1 and 4. Half die 11 has a longitudinal surface cavty 13 along the mating surface and half die 12 has a similar cavty 14. The cavities 13 and 14 define a workpiece receiving area through the tapered split die 10.'

The face end of split die 10 is provided with upset cavty 15 which serves to confine the flow of workpieces held by the die 10 and cause the solid phase union of the workpieces held by the die 10.

In the process of making the improved work holding area through the die 10 according'to the principles of this invention, a cutting devce 'is provided having the general shape of the workpiece to be held in the die and having cutting means in spaced intervals along the surface thereof. One such cutting device is represented by the mandrel 20. Mandrel 20 is provided with a shank end 21 which maybe gripped by any convenient type of holding device, whether that holding device be stationary or rotatable. Abrasive sections 24 are spaced along the surface'of the mandrel 20 to serve as 'cutting means. Cutting devices having .abrasive 'portions adhering to a metallic surface are well known and can be readily adapted for the purpose of this invention. r

In Figure 6 the step of producing lateral recesses is illustrated diagrammatically. The cutting :device is placed in the workpiece holding area of the dies and the dies and the cutting device are rotated relative-to one another under lateral press'ure until lateral grooves are cut in the die member. The die members 11 and 12 may be aligned in the position which they will assume under service conditions, whereupon the holding area defined by the cavities 13 and 14 will have a series of enlarged portions into which the' workpiece may swell in order to provide a tight .interloeking fit with the split die 10. However, it has been found that by staggering the half dies` 11 and 12 substantially as illustrated in Fgure 6, a distance substantially equal to the .distance between the abrasive section 24, that after the lateral cavities have'been cut the half dies can be rematched longitudinallyinto their proper relative position-whereupon the cavities will be alternately spaced with respect to uncut portions of the opposte die member. By this means, the cavities 13 and 14 will define a somewhat meanderng or wavering workpiece holding path through the die. Accordingly, it has been found that a workpiece gripped in such a wavering path will have a considerable resistance to longitudinal movement by vrtue of its shape with respect to the workpiece area, but that the workpiece will not have been stressed to any considerable degree and, consequently, will not have weakness imposed thereon.

An alternate mandrel is illustrated in Figure 7 and indicated by the reference character 22. Mandrel 22, having shank ends 23 thereon for convenient holding, is provided with a series of rounded milling teeth sections 25 thereon. The milling teeth will cut radial grooves in the surfaces of half dies 11 and 12, and if the half dies 11 and 12 are Originally staggered as indicated in Fie 'I'hettypes of rwork holding. area: produced by the: mandrel zz is exceptionallyuvaluable for usetwith insulated: wires which areatotbebuttwelded v Reference to Egures 8 and 9\ willllustrate the nven tion as actually used in butt weld joining of wires under actual serviceconditions... Holders 30are provided in a suitable holding. anddriving tool which will move two tapered split dies 11), alongua common longitudinal path toward and; away from one another. The holders 30 have taperedsockets into which. the. tapered split die 10 will fit and;we dg e. Thecavities 1;3, and 14. are propor; tioned to producea fight grip upon a. workpiece prior to Contacting of the half' dies 11 and 12 in order toassure attight gripuponthevworkpiece. InFgure 8, a wire 31 without insulation is illustrated-,as being the member held bythe. dies 10. In Figure. 8 the 'staggered recesses producedzby the mandrel are; indicatd by the reference character 27-. Here. it; can clearly be seen' that. the recesses 27 are opposite to the land area remaining between the recesses. 27.: of' the, opposite half die member. Thus, the workpiece is pressed by a` land area into .a recess 27. Because. of:` the otfsetnature of' theworkpiece produced by the multiple recess and land areas, the workpiece is caused, tor grip in the. dies with. considerably greater resistance to longitudinal movement. than could be produced by a straight cavity.

In Figure 9 the workpiece. isan'insulated wire 32, and here the advantages' of the rolling type ofmeandering path produced by mandrel 22 is clearly apparent; The insulation. of wre 32- is not cut. orharnfully. deformed and yet the resistance to. longitudinal movement of the r vizite 32 through the dies .10 is.considerablyincreasedt Although the. invention has been describedin its pre-v fet-red form with a certain degree. of particularity, itu is understood that the. presentdisclosurefof. the preferred forms has been made only by way of example and that numerous changes in the details of' construction and the combination and.: arra'ngement of parts mayberesorted to without departing from the spirit and scope of the inven: tion as. hereinafter claimed;

What is claimed is: u

1. The method of making a workpiece cavity in split separating said cutting device from said dies, and placing said dies. into working. ali nmentt wh r n id l t r l grooves are mismatched andcreate a wavering path workpiece holding area.

2. The method of making a Workpiece cavity in splt holding dies, compn'sing the steps of, providing a plurality of die members having complementary mating surfaces; forming a longitudinal groovein the mating surface of each die` member, said. grooves cooperating to defineya lorgitudinal cavity in the mated die providing a mandrel having metal cuttingsurfaces thereon at spaced intrvals along the surface tl'iereof, said cutting surfaces adapted to cut separate recesses placing said dies in longitudir'ially staggered relationship upon said-mandrel; and rotating said mandrel andstaggered dies relative to one another with a lateral pressure closng said dies upon said mandrel until annular recesses are cut in the walls of said grooves.

3. The method of making a workpiece cavity in split holding dies co mprisinglthe steps of, providing a firstland seconddie.memberehaving. omplementary. mated surfaces, formi'ng longitudinalssgrooves inthetmating surface ofeach die member, said grooves. eooperating to defie a longi tudinal.` cavity through the'mated dies, providing a mandrel having a plurality of'cutting surface 'means theron at spaced intervals along the surface thereof, said` cutting V surfaces adap ted. to cut separate. recesses plaing -said dies in longitudinally staggered relationsh'p upon said mandrel', thedies beingstaggered longitudinally a distance substantially equal to the distance between said cutti'ng ally compressible, upon. a workpiece in said area, said die holding dies, comprising. the steps. of providinga plurality I I to the .normal work holding position thereof', placing the cutti'ng device in said workpiece holding area of the staggered dies, rotating said dies and cutting device relative to one another under lateral pressure until matched I I lateral' grooves are; cut in said staggered die members,

members having a. Working alignment position, said die members being relatively shiftable to a staggered relative position, said. die, surfaces, having .symmetrical lateral grooyes along said: Work piece 'holding area While in said staggered relative position, said. lateral grooves having land areas therebetween, said, land' areas, being located opposite groove areas while said die members are in said working; 'alignment position.

er nces t in h file of' th s p t n "ur- 'm n 

